It shows the errors inside a quickfix window, which will allow your to quickly
jump to the error locations by simply pressing [Enter].

Customization
-------------
If you don't want to use the `<F6>` key for PEP8-checking, simply remap it to
another key. It autodetects whether it has been remapped and won't register
the `<F6>` key if so. For example, to remap it to `<F3>` instead, use: